The present invention relates to a sheet reverse apparatus for reversing the surface of a paper sheet on which an image is formed by an image forming apparatus.
In general, in an image forming apparatus such as a copying machine, an electronic printer and the like, an image is formed on one surface of a paper sheet supplied from a paper feed cassette, and the sheet is discharged onto an outlet tray.
In an image forming apparatus of this type, sheets discharged onto an outlet tray are sequentially stacked such that their image surfaces face upward. Therefore, when a sheet is discharged, an operator can immediately and visually check the image formed on it. Unfortunately, however, in so far as the sheets are sequentially stacked in an order opposite the copying order, with the first page being at the bottom and the last page being at the top, it is necessary for the operator to restack the sheets in accordance with the copying or pagination order, a cumbersome task at the best of times, but made even more so as the number of pages increases. For this reason, in place of an outlet tray, a sheet reverse apparatus for reversing and stacking discharged sheets is mounted on the outlet side of the image forming apparatus.
A conventional sheet reverse apparatus incorporates a drive source for driving motors required for a reverse operation, and an exit roller. Due to the presence of the drive source, the overall sheet reverse apparatus becomes large in size and heavy in weight.
In order to solve the above problem, a method has been proposed wherein the drive source is omitted, the drive force required for driving rollers for the reversal of a sheet being supplied from the image forming apparatus. However, in this case, in order to precisely mesh the output gear of the image forming apparatus with the input gear of the sheet reverse apparatus, alignment and machining of these gears requires considerable precision, resulting in high cost.